<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>02DOM练习</title>
</head>
<body>
<h1>我是标题:<span class="s"></span></h1>
<button onclick="f1()">按钮</button>
<br>
<input type="text" id="i1">
<input type="text" id="i2">
<button onclick="f2()">按钮2</button>
<script>
    function f1(){
        let spanE = document.querySelector('.s');
        console.log(spanE);
        spanE.innerHTML='哈哈哈';
    }
    function f2(){
        let input1 = document.querySelector('#i1');
        let input2 = document.getElementById('i2');
        console.log(input1.value);
        console.log(typeof  input2.value);
        let i2=parseFloat(input2.value);
        console.log(i2,typeof i2);
    }
</script>
</body>
</html>